The caduceus is the traditional symbol of Hermes and features two snakes winding around an often winged staff. It is often used as a symbol of medicine, especially in the United States, despite its ancient and consistent associations with trade, liars, thieves, eloquence, negotiation, alchemy, and wisdom. The modern use of the caduceus as a symbol of medicine became established in the United States in the late 19th and early 20th century as a result of well-documented mistakes, misunderstandings of symbology and classical culture. The correct symbol for medicine is the Rod of Asclepius, which has only one snake and no wings. Early use in a possible medical context Before the ancient Romans and Greeks (about 2612 BCE), older representations from Syria and India of sticks and animals looking like serpents or worms are interpreted by some as a direct representation of traditional treatment of dracunculiasis, the Guinea worm disease. While there is ample historical evidence of the use of the Caduceus, or Herald's Staff, to represent Hermes or Mercury (and by extension commerce and negotiation), early evidence of any symbolic association between the Caduceus and medicine or medical practice is scarce and ambiguous. It is likely linked to the alchemical "universal solvent", Azoth, the symbol of which was the caduceus. The Guildhall Museum in London holds a 3rd-century oculist's seal with Caduceus symbols both top and bottom. The seal was apparently used to mark preparations of eye medicine. It is believed likely that rather than being evidence of a medical association per se, this is rather an allusion to the words of the Greek poet Homer who described the Caduceus as "possessing the ability to charm the eyes of men", which relates to the business of an oculist. Walter Friedlander proposed that early association of the Caduceus with medicine might have derived from the association of Hermes Trismegistus ("Thrice-Great Hermes") with early chemistry and medicine as aspects of alchemy as an esoteric practice. He notes that "there are very definite connections between medicine and (Hermes)-Thoth, who later became known as Hermes Trismegistus. ... although these various factors may link Hermes/Mercury, along with his Caduceus, with alchemical medicine, they may just as well link all the other non-medical aspects of alchemy with Hermes/Mercury and the Caduceus". Medieval times The Caduceus became a symbol of alchemy and pharmacy in medieval Europe. Its first appearance as a medical symbol can be traced